Ultra high frequency magnetron discharge tube circuit



.May 4, 1937. FRlTz 2,079,248

ULTRA HIGH FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT Filed Sept. 19,1935 s Sheets-Sheet 1 F. 5 5+ F; ,4 A1040 INVENTOR.

ARL FRITZ BY vkz ATTORNEY.

May 4, 1937. 2,079,248

ULTRA HIGH FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT I K. FRITZ FiledSept. 19, 1935 '3 Sheets-Sheet 2 IN\ E\TOR. KARL FRITZ ATTORNEY.

' May 4, 1937.

K. FRITZ ULTRA HIGH FREQUENCY MAGNETRON DISCHARGE TUBE CIRCUIT 3Sheets-Sheet 5 Filed Sept. 19, 1935 INVENTOR. KARL FRITZ g rv-{A/ATTORNEY.

Patented May 4, 1937 ULTRA HIGH. FREQUENCY MAGNETRON DISCHARGE TUBECIRCUIT Karl Fritz, Berlin, Germany, assignor to Telefunken Gesellschaftfiir Drahtlose Telegraphicv m. b. 11., Berlin, Germany, a corporation ofGermany Application September 19, 1935, Serial No. 41,223 y In GermanySeptember 4, 1934 11 Claims.

The present invention is concerned with a circuit arrangement designedfor the generation, detection, amplification, and multiplication ofoscillations, more particularly of ultra-high frequency oscillations. Itrelates also to electron discharge tubes of the magnetron type and ofsuitable design for controlling the paths of electrons.

What is meant here by-a magnetron is a charge tube in which a constantor a varying magnetic field governs the path or trajectory ofelectricity carriers. at least a cathode and an anode 'or plate. Withouta magnetic field, it is incapable of fulfilling its function, because itis the magnetic field which produces a useful non-linearity of the tubecharacteristic in the neighborhood of the working point.

For the production and the reception of radiofrequency oscillations, it'is known from the prior art that magnetron tubes may be excited by theaid of direct current magnetic fields. It is likewise known that foramplifying relatively lowfrequency oscillations a magnetron may beoperated when its magnetic field is excited by an alternating current.The lines'of force of the field are in both cases rectilinear inside thedischarge'path and parallel in reference to the axis of the anode systemor the heating wire.

Then again it isknown that in an electron tube having a grid aninfluence over .the passage of electrons from the cathode to the anodemay be produced by the magnetic field set up by the current flowingthrough the heating wire, the said field surrounding, the heater wireannularly (see Barkhausen, Elektronenroehren, Vol. 1, 1931, p.

.- The impress of control currents upon the cathode itself for purposesof field excitation has not proven satisfactory. However, bycontrollingthe intensity of the magnetic field presenting circularsymmetry to the cathode, the paths ofthe electrons in the vicinity ofthe control electrode may be given such a'curvature that the effective 4tube characteristic is substantially altered. Radio frequency control ofthe electrons is then effected by utilizingthe capacitive reactions be-'dis- Such a magnetron contains tween the electrodes. In all cases,however, the cathode is included in the oscillatory circuit.

The magnetron circuit arrangement of this invention is especially welldesigned for the generation, reception, detection, amplification or fre-5 quency multiplication of ultra-short waves. It has this outstandingcharacteristic feature that for the purpose of acting upon the paths ofthe electrons, recourse is had to a circular-symmetric magnetic fieldwhich is set up by the aid of a linear conductor which is normally notheated and which is placed symmetrically'in reference to the anodesurface. I

Before entering into a discussion of the special merits of the circuitorganization hereinafter to be disclosed, a brief outline will be givenof the construction and mounting of the tubes comprised therein.Particularly suited for the present scheme are tubes built assymmetrically as feasible and which comprise at least two anode parts asin an ordinary split anode magnetron. The anodes form an approximatelyclosed hollow surface of revolution. The linear conductor beforementioned (hereinafter called the deflector) which serves to create thecircular-symmetric magnetic field forms the axis of rotation of theseveral anode members. 'Directly or nearly in the electric and thegeometric points of symmetry of the system comprised by the-deflectorand anode members, at close proximity to the former, are arranged thepunctiform or circular electron emission sources.

The chief advantage of circuit schemes as he disclosed resides in thefact that no extraneous magnetic field is required; The heretofore usedtroublesome. and heavy magnet systems and the source for energizationthereof are dispensed with. The circular-symmetric magnetic field is nowproduced by the aid of a current traversing the'defiector. Theincidental expenditure of energy is either reduced to negligible valuesor no energy at all is supplied, as, for instance, when radio frequencycurrent control-results from a self-oscillatory scheme. v 1

The anode members form an approximately closed surface presentingrotation symmetry. Each of the anode members of the embodiments shown inFigs. 1 to '7 inclusive and 11 to 13 inclusive is preferably conformedto a spherical surface. Theanode' members of the embodiments shownin'Flgsl 8 and 9 are preferably cylindrical in shape. The anodes of theembodiment shown in Fig. 10 are partly cylindrical and partly conical.In every case, however, "the anode members constitute shielding meanswhereby the discharge path is protected against outside fields. Theclosed form of anode, moreover, makes conditions so that the radiationresistance of the electrode assembly or system is minimized. Suchradiation as may exist is restricted to the breadth of slit. Thus Iavoid the wasteful dissipation of a large part of the generated energy.

In contrast with the prior practice, where usually the radio frequencycontrol field and the static accelerator field were superimposed on thesame discharge path, the electron paths are maintainedalways in adirection away from the oathode. In other words, the stream of electronsin'the present scheme is caused to proceed by tions of space underconditions which, from the viewpoint of time, have been madenon-equivalent by the oscillation process. This point is extremelyessential seeing that it renders the use of highemission oxide-coatedcathodes (having no pronounced saturation) possible. These cathodesrepresent an extremely abundant and copious electron source per unit ofsurface or area. It will be remembered that in practically allultrashort-wave tube generators, a limitation is imposed upon the loadby the cathode rather than by the anode, asis normally true. Thedimensions of the cathode grow with the aggregate electron emission.This circumstance, in shortwave tubes, makes itself very disagreeablyfelt inasmuch as the proportions of the other electrodes grow with thecathode, so that a tube of this kind finally becomes unserviceable forthe generation of ultra-short waves for this specific reason that theoscillatory circuit formed by the electrodes and their connections orleads exhibits an unduly low natural frequency. In con-v nection withthese problems it has been suggested to use for short-wave tubes, moreparticularly, magnetron tubes, a vacuum spark-gap,

an are or some other unassisted gas discharge path as a source whence toderive electrons, and

\ this opens up wholly new vistas for the creation 'of novel circuitorganizatiofis and for the use of circuit schemes known in the earlierart for the generation of ultra-short waves.

My invention will best be understood from the following detaileddescription when read in view of the accompanying drawings in whichFigure 1 is a circuit diagram of an oscillation generator and amplifierin which the principles of my invention are illustrated;

Figs. 2, 3, 4 and 5 show various modifications suitable for frequencymultiplication;

Figs. 6 and '7 show self-sustaining oscillation generators of twodifferent types;

Fig. 8 shows a push-pull type of self-sustaining oscillation generator;

Fig. 9 shows a master controlled radio-frequency amplifier;

Figs. 10 and 11 show two illustrative embodiments in eachof which theoscillation circuit'is combined with the utilizationcircuit; and

Figs. 12 and 13 illustrate two difierent receiving circuits wherein theinvention is carried out.

Fig. 1 illustrates the fundamentals of a magnetron type oscillator ofthe kind here disclosed and designed for master operation andexcitation. Control action upon the electrons in a tube R113 obtained byan alternating magnetic field presenting circular symmetry. The cathodeI0 is confined to a space as close to the center of the spherical anodesas it is possible to place it. In the figure, it is shown in section andit will be understood to be looped around the conductor S while beinginsulated therefrom. As is well known in the operation of magnetrontubes, the emission of electrons from a centrally disposed cathodetoward a surrounding system-of anodes is such that the electronsdescribe spiral or hellcal paths under the influence of a polar magneticfield whose axis is coincident with the helical axis. If the polarity ofthe magnetic field is reversed, then the direction of rotation of theelectrons around the polar or helical axis will be reversed. Theconductor S is adapted to carry a heavy alternating current. The spiralpaths of the electrons emitted from the cathode 10 will be divertedtoward first the anode A1 and then the anode A2 in accordance with thereversal of current in the conductor S. Hence, oscillations will beproduced in the closed loop circuit including the anodes A1 and A2,together with the inductance L. In the present instance, the controlcurrent is assumed to be derived from master os- CillSAiOlbRz. Theoscillatory circuit of the master oscillator R2, and the control circuitcomprising deflector S and capacitance C of tube R1 are connected bymeans of a suitable feeder K, having a linear conductor 2| whichisdisposed in inductive relation to the conductor 20. The amplifiedradio frequency energy may be derived from the oscillation circuitconsisting of the inductance L and the mutual capacitance between theanode members A1 and A2, or. in any other convenient manner.

The magnetron oscillator of this invention subject to magnetic mastercontrol action represents a separately excited ultra-short-wavetransmitter which is sensibly free from reactions. In the operation ofmagnetrons subject to master voltage excitation it has never beenpossible in the prior art to preclude completely the reactions or themain transmitter upon the master oscillator. Because of the diminutiveproportions of the electrode systems under present consideration it isextremely diiiicult in actual practice to prop-' erly locate the neutralsymmetry planes or electric bridge points of the system orto accommodatetherein the entire means for obtaining voltage control action. Thediiliculties attendant upon amplification of ultra-short waves arelargely due to the inter-electrode capacitances which produce currentsthat are improperly phased with respect to the space current energy.Upon attempting to surpass previous limits of high frequency generation,the displacement currents ultiniately exceed the electronic currents sothat the amplifier as such becomes useless.

In order to meet these difllculties my inventio 1 may be utilized toconsiderable advantage. Inastrol circuit C--20S-,-20. In this and insimilar schemes the radio-frequency potential between anode members A1and A2 is immaterial so far as the electron paths M and 12 areconcerned.

electrons subject to the influence of an alternating magnetic field I 3and l4 respectively, during two different alternations. A usefuloscillation current may be derived from the amplifier R1 .by coupling autilization device to the inductance L. This current will not reactadversely upon the electron' control action. Moreover, the phaserelations between the control current flowing in S and the alternatingvoltage between A1 and A2 'is immaterial, seeing that the oscillatorycir-- cults are completely separated one from the other. Save for suchlosses as are generally inevitable, the control action is free fromdissipation of energy. Figs, 2 to 5, fundamentally, show magnetronoscillators similar to the one in Fig. 1, though operating as frequencymultipliers. The frequency derived at the output end is higher than thefrequency put into the control circuit C20S-20.- Frequencymultiplication is obtained by virtue of the rotation-symmetric anodesurface which is split into a plurality of ring-like members A1, A2, As,etc. These anode members may be conformed to a spherical surface and areinter-connected by way of inductances I! which bear a relationship tothe desired output frequency. The connection of the anode members withthe plate-potential source may be effected in such a fashion that theoscillations of higher frequencywhich are excited during the variousphases of the fundamental input frequency become additively superposedin the load circuit, or in their field in case of direct radiation.

In a frequency-multiplier magnetron it is usual to provide a singlecathodeor electron supply source. This cathode is placed in thegeometric center of the system consisting of the currentpath and theanode members. The rotationsymmetric surfaces of electron paths inpositions sively during each cycle of the fundamental frequency. Thiselectron fan is subject to the control of deflector action of the radiofrequency II and I2 represent the paths of two i, 2, 8, l, 8, etc.become eifective succes current flowing through S and produces a sweepof the electrons across the constituent anode splits A1, A2, A: Thelength of time for which the electron fan stays on each anode membermust be uniform and equal. The breadth of the annular anode splits ormembers must be chosen with due regard for the instantaneous angularspeed of the electron fan, and the frequency mu]; tiplier factor is afunction of the number of the anode splits.

The useful output energy'at the multiple frequency may be taken over byan inductive coupling between the various loop circuits I1 and thesingle loop IS, the terminals of which are capacitively coupled at [9 asshown in Fig. 2. In Fig. 3

.the same inductive relationship exists between the loops 22 and therlng 23, the terminals of which are inter-coupled capacltively at 2'4.The ring 23 may, if desired, comprise a radiator.

In Fig. 4 the frequency multiplier action may be caused to impressthe'desired multiple .frequencynpon a coil 15 which is inductivelyrelated to a coil IS in a load circuit.

Fig. 5 shows a frequency multiplier wherein the several anode membershave output leads 25 all inter-connectedata radio frequency nodal point:5 so as to be supplied with anodepotential from any suitable directcurrent source as indicated at +3. The separate leads 25 may beinductively coupled to a loop 18 in an output circuit which alsoineludes the capacitor i9.

Referringto Fig. 6 I show another modification of my .invention. A selfoscillatory magnetron circuit is provided. In this embodiment there aretwo anode members A1 and A2 of hemispherical formation. The members 29are capacitively coupled thereto. The capacitive members 29 are incircuit with an inductance 28 from which output energy may be derived inany suitable manner. The oscillator circuit includes the' cathode 10which is fed by heating current'through the twisted pair of wires 25,this current being de rived from any suitable source as through thetransformer 26. A center tap on the secondary of this transformer leadsto the negative side of a direct currentsource 27 and the positive sideof this source is suitably connected to the deflector conductor S. Thiscircuit is subject to control action by a circular-symmetric alternatingmagnetic field. The oscillatory circuit of the oscillator consists ofthe capacities of the anode members A1, A2, and the inductance of thedeflector conductor S. The oscillation circuit itself, as will thus benoted, controls the flow or passage of electrons from the source I 0 tothe anode splits A1, A2. up by the oscillatory current moves about theconductor S as the axis of circular symmetry. The electron source II) isdisposed at a neutral 'point I of the entire system and is formedsymmetrically about conductor S. The phase shift required for theself-excitation of oscillations between the controlled electron streamand the plate alternating voltage must be secured by adjustment of thereactions in relation to the transit time of the electrons. Inasmuch asthere is usually a phase angle of 90 degrees between current andvoltage, it is necessary to. correct the phase relations. The simplestplan is to so adjust the constant current plate voltage with respect tothe frequency determined by the oscillatory circuit of the tube that thefinite transit time of the electrons will restore the requisite phaserelation.

In the case of a magnetron of the self-oscillatory radio-frequencycurrent control type, the presence of a high capacity in the oscillationcircuit, as provided by the cooling means 29 adjacent the anode is veryadvantageous since the ratio L/Cshould be kept low for maintaining acontrol current of high amplitude.

Fig. 7 shows still another self-oscillatory mag-' netron oscillatorsubject to audio frequency modulation control. Inside the deflectorconductor S, and insulated from the latter by insulation 30 The activemagnetic field set is disposed a conductor 3! which may be employed formodulating the currents of the oscillation generator. The modulationsource is shown at 32 and is coupled through the transformer 33 to thecontrol circuit including the conductor 38.

The use of a circular-symmetric magnetic field designed to influence theelectron paths is not limited to radio frequency current control;

in fact, the same field may be controlled to similar advantage byvoltage variations. If in this case a push-pull actionis to be desired,then the anode of the voltage-controlled self-oscillatory magnetron mustbe split at least twice, as shown in Fig. 8. The oscillatory circuitisinterpositioned between the anode members 36 and 31, or correspondinganode groups. The sense of flow of electrons is in this, instancedetermined byv the direction of a constant magnetic field... The designof the magnetron tube shown in Fig. 3 is such that two cathodes E1 andE2 are provided. Typical electron paths from these electrodes to thesurrounding anodes are delineated on the drawingsin one case by solidlines extending from the cathode E1 and in the other case by dottedlines extending from cathode E2. In this embodiment phase shift isunnecessary because the radio frequency potentials which exercise acontrol action upon the stream of electrons are due to regeneration andto the oscillatory characteristics of the output circuit. I

It is reasonable to assume that in the operation of this embodiment, acloud of electrons will be concentrated first upon the anode-36 and thenupon the two anodes 31, thus producing a radio frequency current in thetransformer 35. Suecessful operation of the device is, however, by nomeans dependent upon the correctness of this theory.

To those skilled in the art, the circuit of Fig. 8 may easilybe'modified to include certain of the features of Fig. 1, thus providinga master-controlled, push-pull amplifier. Fig. 9 also suggests 5 a meansfor accomplishing this end. Here the I I through zero, or twice percycle of the modulation anode members 38 serve as push-pull excitersunder control of energy from the source K. Si: multaneously, the anodemember 36 oscillates in phase opposition to the anode members 31.

Upon producing a circular-symmetric and conbe introduced into theoscillator also when the same is subject to magnetic modulation, say, bythe agency of a conductor 3| positioned co-axially in reference to thedeflector as shown in Fig. '7. So, as seen in Fig. 9, the electronsupply sources I!) are slightly displaced from the separating planesbetween the anode members. Now if the anode splits receive exactly equaldirect current voltages, a frequency twice the modulation frequency willarise in the output circuit because the crest of the alternating currentwave occurs upon each passage of the modulation current frequencyElectric dissymmetry is obtainable by impressing dissimilar potentialsupon the platev splits. 'Magnetic dissymmetry is readily securable by asuperposed auxiliary field of the desired direction and magnitude.

Delivery of the radio'frequency output current to a' utilization circuitmay be made by inductive or capacitive coupling or conductively if-stricted to the exemplified embodiments illusdesired. But the mode ofdelivery isnot retrated in the drawings. In fact, any suitable and wellknown transfer means may be employed. Fig. 10 shows an example ofcapacitive transfer means. applied directly to the deflector conductorS.

Fig. 11 shows a self-oscillatory alternating current-controlledmagnetron in which a. spark or are discharge path is used as the sourceof the electrons? The'pscillation circuit consists of the two anodeparts A1 and A'r'and the conductor S.

At the extensions V of the latter, say, outside the discharge vessel,conductor S is fitted with capacia anodes.

tive balls Bby the aid of which the radiation resistance of the dipolearms V can be adjusted to obtain an impedance match with respect to theinternal impedance of the oscillator at the working frequency. Insidethe conductor S, and separated therefrom by insulation 30, are the twodischarge electrodes F. The discharge gap is excited bymeans of aconductor 44 which is brought out at suitable nodal points along theextensions V of conductor S and thence through a resistance 45 to asource of current 46. The electric center of the source of emission isartificially imitated outside the oscillator. Modulation of theoscillator is obtained magnetically. In this instance, also, thedeflector or conductor S must carry the modulation frequency in additionto radio frequency. Anode potential is supplied by way of a mid-tap onthe secondary winding of a modulation transformer 41 and thence throughleads -Z to the anode parts A1 and A2. The conductor S, which in thiscase surrounds the discharge path, is provided above the electron sourcewith apertures 48 designed to allow of the escape of the electrons. Inorder to concentrate or focus the fan or beam of electrons, auxiliaryelectrodes H insulated fromS are provided, and these m be raised to anydesired potential.

Figs. 12 and 13 illustrate two different embodiments of receivingcircuits. The receiving dipole comprises an extended conductor S. Thisdipole is arranged tobe excited with electrical energy from end to endas induced therein by received radiant energy. The currents induced inthis dipole, therefore, act to deflect the paths of electrons from thecathode I0 to the surrounding When the apparatus is employed as areceiver it is unnecessary for the dipoleconductor S to beelectrically'connected to any other portions of the device. Witha viewto enhancing the directional properties the entire arrangement may befurnished with a reflector or mirror. The electron source I0 is shown atthe center of the system. A1, A2 and A3 are anode members or splits.Adjustments are made so that in the absence of signals substantially theentire electron emission current flows to the central split A3. Hence,the electron fan must be so formed that, when striking the central anodemember M, it will roughly have the same width as that member... I

The receiving circuit ,of Fig. 12 comprises a bridge rectifier 49 and asound responsive device 50 so connected to the anodemembers A1, A2

and A: that full wave rectiflcation'of the modulation frequency. may beimpressed across the ;terminals of the sound responsive device. Thecathode I0 is energized in the same manner as shown in Fig. 6, while'anode potential may beimpressed upon the anodes from the directcurradio frequency signal is received upon the dipole antenna S amagnetic fleld will'be produced symmetrically about this conductor so asto control the direction of eiectronic flow, first to the left, "andthen to the right, thereby setting up the electronic .fan action asheretofore explained. The amplitude of the electronic swings thusprovides,a corresponding response 'in the receiver 50 because only thedemodulation currents can traverse .the windings of. the device 5|! whenconnected through the bridge rectifier as shown.

Fig. 13 shows an embodiment of receiving apparatus which differs fromthat of Fig. 12 chiefly trol circuit CS,-20. In this-and in similarschemes the radio-frequency potential between anode members A1 and A2 isimmaterial so far as the electron paths II and I2 are concerned.electrons subject to the influence of an alternating magnetic field BandI! respectively, during two different alternations. A useful oscillationcurrent may be derived from the amplifier R1 by coupling a utilizationdevice to the inductance L. This current will not react adversely uponthe electron control action. Moreover, the phase relations between thecontrol current flowing in S and the alternating voltage between A1 andA2 is immaterial, seeing that the oscillatory circuits are completelyseparated one from the other. Save for such losses as are generallyinevitable, the control action is free from dissipation of energy. 20Figs. 2 to 5, fundamentally, show magnetron oscillators similar to theone in Fig. 1, though operating as frequency multipliers. The frequencyderived at the output end is higher than the frequency put into thecontrol circuit C20-S20. Frequency multiplication is obtained by virtueof the rotation-symmetric anode surface which is split into a pluralityof ring-like members A1, A2, Aaetc. These anode members may be conformedto a spherical surface and are inter-connected by way of inductances I!which beara relationship to the desired output frequency. The connectionof the anode members with the plate-potential source may be effected insuch a fashion that the oscillations of higher frequencywhich areexcited during the various phases of the fundamental input frequencybecome additively superposed in the load circuit, or in their field incase of direct radiation.

In a frequency-multiplier magnetron it is usual to provide a singlecathodeor electron supply source. This cathode is placed in thegeometric center of the system consisting of the currentpath and theanode members. The rotationsymmetric surfaces of electron paths inpositions sively during each cycle of the fundamental frequency. Thiselectron fan is subject to the control or deflector action of the radiofrequency II and i2 represent the paths of two' suitable direct currentsource as indicated at +3.

to a loop l8 in an output circuit which also includes the capacitor l9.

Referring to Fig. 6 I show another modification of my invention. A selfoscillatory magnetron circuit is provided. In this embodiment there aretwo anode members A1 and A2 of hemispherical formation. The members 29are capacitively coupled thereto. The capacitive members 29 are incircuit with an inductance 28 from which output energy may be derived inany suitable manner. The oscillator circuit includes the' cathode IIIwhich is fed by heating current through the twisted pair of wires 25,this current being derived from any suitable source as through thetransformer 26. A center tap on the secondary of this transformer leadsto the negative side of a direct currentsource 21 and the positive sideof this source is suitably connected to the deflector conductor S. Thiscircuit is subject to control action by a circular-symmetric alternatingmagnetic field. The oscillatory circuit of the oscillator consists ofthe capacities of the anode members A1, A2, and the inductance of thedeflector-conductor S. The oscillation circuit itself, as will thus benoted, controls the flow or i, 2, 6, I, 8, etc. become effective succescurrent flowing through S and produces a sweep 50 of the electronsacross the constituent anode splits A1, A2, A: The length of time forwhich the electron fan stays on each anode member must be uniform andequal. The breadth of the annular anode splits or members must be chosenwith due regard for the instantaneous angular speed of the electron fan,and the frequency multiplier factor is a function of the number of theanode splits.

The useful output energy'at the multiple frequency may be taken over byan inductive coupling between the various loop circuits [1 and thesingle loop l8, the terminals of which are capacitively coupled at I!)as shown in Fig. 2. In Fig. 3 the same inductive relationship existsbetween the loops 22 and the ring 23, the terminals of which areinter-coupled capacitively at 2'4. The ring 23 may, if desired, comprisea radiator.

In Fig. 4 the frequency multiplier action may be caused to impressthei'desired' multiple .fre quencyupon a coil [5 which is inductivelyrelated to a coil IS in a load circuit.

Fig. 5 shows a frequency multiplier whereinthe several anode membershave output leads 25 all inter-connected at"a radio frequency nodalpoint 35 so as to be supplied with anodepotential from any passage ofelectrons from the source ill to the anode splits A1, A2. The activemagnetic field set up by the oscillatory current moves about theconductor S as the axis of circular symmetry. The electron source I0 isdisposed at a neutral point of the entire system and isformedsymmetrically about conductor S. The phase shift required for theself-excitation of oscillations between the controlled electron streamand the plate alternating voltage must be secured by adjustment of thereactions in relation to the transit time of the electrons. Inasmuch asthere is usually a phase angle of 90 degrees between current andvoltage, it is necessary to correct the phase relations. The simplestplan is to so adjust the constant current plate voltage with respect tothe frequency determined by the oscillatory circuit of the tube that thefinite transit time of the electrons will restore the requisite phaserelation.

In the case of a magnetron of the self-oscillatory radio-frequencycurrent control type, the presence of a high capacity in the oscillationcircuit, as provided by the cooling means 29 adjacent the anode is veryadvantageous since the ratio L/Cshould be kept low for maintaining acontrol current of high amplitude.

Fig. 7 shows still another self-oscillatory mag-' netron oscillatorsubject to audio frequency modulation control. Inside the deflectorconductor S, and insulated from the latter by insulation 30 The separateleads 25 may be inductively coupled is disposed a conductor 35 which maybe employed for modulating the currents of the oscillation generator.The modulation source is shown at 32 and is coupled through thetransformer 33 to the control circuit including the conductor 3i.

The use of a circular-symmetric magnetic field designed to influence theelectron paths is not limited to radio frequency current control;

in fact, the same field may be controlled to similar advantage byvoltage variations. If in this case a push-pull actionis to be desired,then the anode of the voltage-controlled self-oscillatory magnetron mustbe split at least twice, as shown in Fig. 8. The oscillatory circuit'isinterpositioned between the anode members 36 and 31, or correspondinganode groups. 'The sense of flow of electrons is in this instancedetermined by the direction of a constant magnetic field. The design ofthe magnetron tube shown in Fig. 3 is such that two cathodes E1 and E2are provided, Typical electron paths from these electrodes to thesurrounding anodes are delineated on the drawings in one case by solidlines extending from the cathode E1 and in the other case by dottedlines extending from cathode E2. In this embodiment phase shift isunnecessary because the radio frequency potentials which exercise acontrol action upon the stream of electrons are due to regeneration andto the oscillatory character: istics of the output circuit.

It is reasonable to assume that in the operation of this embodiment, acloud of electrons will be concentrated first upon the anode-36 and thenupon the two anodes 31, thus producing a radio frequency current in thetransformer 35. Successful operation of the device is, however, by nomeans dependent upon the correctness of this theory.

To those skilled in the art, the circuit of Fig. 8 may easilybe'modified to include certain of the features of Fig. 1, thus providinga master-com trolled, push-pull amplifier. Fig. 9 also suggests a meansfor accomplishing this end. Here the anode members 38 serve as push-pullexciters under control of energy from the source K. Simultaneously, theanode member 38 oscillates irf phase opposition to the anode members 31.

Upon producing a circuiar-symmetric and constantly unidirectionalmagnetic field around the be introduced into the oscillator also whenthe same is subject to magnetic modulation, say, by the agency of aconductor 3| positioned co-axially in reference to the deflector asshown in Fig. 7. So, as seen in Fig. 9, the electron supply sources IDare slightly displaced from the separating planes between the anodemembers. Now if the anode splits receive exactly equal directcurrentvoltages, a frequency twice the modulation frequency will arisein the output circuit because the crest of the alternating current waveoccurs upon each passage of the modulation current I through zero, ortwice per cycle of the modulation frequency' Electric dissymmetry isobtainable by impressing dissimilar potentials upon the plate splits.'Magnetic dissymmetry is readily securable by a superposed auxiliaryfield of the desired stricted to the exemplified embodimentsillusdirection and magnitude.

Delivery of the radio'frequency output current to a utilization circuitmay be made by inductive or capacitive coupling or conductively ifdesired. But the mode of delivery isnot retrated in the drawings. Infact, any suitable and well known transfer means may be employed. Fig.10 shows an example of capacitive transfer means. applied directly tothe deflector conductor S.

Fig. 11 shows a self-oscillatory alternating current-controlledmagnetron in which a spark or are discharge path is used as the sourceof the "electrons The, oscillation circuit consists of the two anodeparts A1 and Arand the conductor S.

At the extensions V of the latter, say, outside the discharge vessel,conductor S is fitted with capacie tive balls B by the aid of which theradiation resistance of the dipole arms V can be adjusted to obtain animpedance match with respect to the internal impedance of the oscillatorat the working frequency. Inside the conductor S, and separatedtherefrom by insulation 30, are the two discharge electrodes F. Thedischarge gap is excited by means of a conductor 44 which is brought outat suitable nodal points along the extensions V of conductor S andthence through a resistance to a source of current 46. The electriccenter of the source of emission is artificially imitated outside theoscillator. Modulation of the oscillator is obtained magnetically. Inthis instance, also, the deflector or conductor S must carry themodulation frequency in addition to radio frequency. Anode potential issupplied by way of a mid-tap on the secondary winding of a modulationtransformer 41 and thence through leads 2 to the anode parts A1 and A2.The conductor S, which in this case surrounds the. discharge path, isprovided above the electron source with apertures 48 designed to allowof the escape of the electrons. In order to concentrate or focus the fanor beam of electrons, auxiliary electrodes H insulated from S areprovided, and these m be raised to any desired potential.

Figs. 12 and 13 illustrate two different embodiments of receivingcircuits. The receiving dipole comprises an extended condu'ctor S. Thisdipole is arranged to be excited with electrical energy from end to endas induced therein by received radiant energy. The. currents induced inthis dipole, therefore, act to deflect the paths of electrons from thecathode iii to the surrounding anodes. When the apparatus is employed asa receiver it is unnecessary for the dipole conduc- -tor S to beelectrically conpected to any other portions of the device. Witha viewto enhancing the directional properties the entire arrangement may befurnished with a reflector or mirror. The electron source i0 is shown atthe center of the system. A1, A2 and A3 are anode members or splits.Adjustments are made so that in the absence of signals substantially theentire electron emission current flows to the central split A3. Hence,the electron fan must be so formed that, when striking the central anodemember As, it will roughly have the same width as that member. I

The receiving circuit of Fig. 12 comprises a bridge rectifier 49 and asound responsive device so connected to the anode members A1, A: and A:that full wave rectification-of the modulation frequency may beimpressed across the ;terminals of the sound responsive device. Thecathode i0 is energized in the same manner as shown in Fig. 6, while'anode potential may be impressed upon the anodes from the directcurrent source 21 and leading through the rectifier bridge 49.

It should be apparent that when an ultra-high radio frequency signal isreceived upon the dipole in the mode of connectionof the anode membersthe electron discharge .tube structure.

ALA: and A3 to the sound responsive device 50. There. a full .waverectifier 5| is suitably connected with the sound responsive device 50and with the anode membersAi and A2 for demodulating the currentsarising upon the reception of the modulated ultra-high frequencysignals. This circuit also includes choke coils 52 disposed between theanode potential source 21 and the anode members A1 and A2 so as to avoidthe dissipation of ultra-high frequency energy. If desired, auxiliaryelectrodes 43 may be included in These electrodes will be understood tohave impressed upon them a suitable direct current bias potential inorder to further control the electronic action within the tube.

I claim: r

1. In an ultra high frequency circuit, a magnetron discharge tube havinga plurality of anode members the inner surfaces of which aresubstantially conformed to a spherical surface, a cathode disposed asnear as possible to the center of the spherical system, a magneticfieldproducing conductor extending diametrically through the sphericalsystem, means for so en-' ergizing the cathode and the anode members asto set-up electronic emission therebetween, means for applyingalternating potentials to said fieldproducing conductor for variablycontrolling the direction of electronic paths within the tube, and meansfor utilizing the output energy available from different ones of saidanode members when in circuit with the cathode 2. A device in accordancewith claim 1 ,and

having the anode members conformed to latitudinal zones of the sphericalsystem, and having the field-producing conductor axially disposed withrespect to said zones.

3. A device in accordance with claim 1 and having means for multiplyingthe frequency of the energy impressed upon said field-producingconductor. I 4. A device in accordance with claim 1 in whic 45 saidmeans for applying alternating potentials to said field producingconductor is constituted by a master oscillator. I

5. Adevice in accordance with claim 1 wherein said field producingconductor forms part of a resonantcircuit the impedance values of whichare such that self-sustaining oscillations may be generated therein.

6. A self-oscillating magnetron discharge tube circuit having aplurality of spherically segmerited anode members and a centrallydisposed cathode included in the electron discharge tube thereof, meansincluding a conductor perpendicularly disposed with respect to theplanes of segmentation of said anode members for producing a deflectionof electronic emission successively toward different ones of said anodemembers, and means for compensating for the phase displacement of theanode currents with respect to input currents impressed upon saidperpendicularly disposed conductor, which phase displacement isinherently due to the transit time of the electrons from the cathode toeach anode member.

'7. A circuit in accordance with claim 6 and having a source of directcurrent potential connected between the cathode and the anode membersand of'such value asto obtain the desired compensation for phase shift.

8. A circuit in accordance with claim 6 and having means including anadditional conductor concentric with said perpendicularly disposedconductor for impressing modulations upon the oscillations generated.

9. A circuit in accordance with claim 6 wherein said cathode is dividedinto ring-like members coaxially disposed with,respect to saidperpendicular conductor said ring-like members being so spaced apartlongitudinally of said perpendicular conductor that they constitutemeans for directing the normal flow of electrons toward the gapsbetweenadjacent anode members.

" 10. A- circuit in accordance with claim 6 and having means includingcertain of said anode members for exercising a control action upon theelectronic emission which is directed toward others of said anodemembers.

11. A circuit in accordance with claim 6 and having means including adipole antenna system for the transmission and reception of ultra-highfrequency energy, said means constituting extensions of saidperpendicularly disposed con- .ductor.

